I recently purchased a chronograph based from all the advise I have read here. I've used it twice since getting it. Something seems to be amiss. Can the calibration really be off from the factory and if so, how does one remedy this?

Does the distance from the end of the barrel to the first diffuser make that much of a difference and if so, what is the distance everyone uses?

I have been shooting a .300WinMag with 30in barrel. I reloaded 74.3grs RL-22 underneath a 190gr Berger VLD and Fed Mag Rifle primer. I fired five rounds today to get an approximate 1" group at one hundred yards. The Chrony consistently listed those 5 shots between 3235 and 3250fps. This seems a tad fast. I then shot 5 180gr Nosler Partitions using the same load. While the accuracy wasn't there the velocity increased to approximately 3720fps. All printed the same basic place on the targets...so while I gather a few extra inches in barrel length can increase speeds a tad bit...I doubt that a 10 grain drop in bullet weight accounts for a 500fps increase in velocity. What could I possibly be doing wrong, coz I know I gotta be doing something wrong...LOL!

Electronic chronographs are generally 1% or less inaccurate. I'd go with what it tells you. If nothing else, it gives you a baseline from which to work. And could a ten-grain difference in bullet weight deliver a 500 fps difference given the same powder charge? Sure! At the pressures created by so much powder, it's not unbelievable that a 500 fps increase is certainly possible. Add to that, physics never lies.

Most people place the chrono about fifteen feet from the muzzle...

magnums have a lot of muzzle flash> and even my 25/06 i like to be about 15' from the muzzle.
you need to shoot at least 1 shot before shooting a string.
Dve

I check mine each time I use it with my .22LR just to be sure I am square and parallel to the unite before I waste any center fire ammo. It also lets me verify the speed as being the same as the last session.

As posted, you may be too close to the end of your rifle and are getting a reading off of your muzzle blast.
I set my unit up at least 15' from the end of the rifle. 20' is I'm shooting boomers. You can proof your unit using match 22 ammo. The velocities on the box are usually pretty close to actuality.

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Originally posted by wasbeeman:
As posted, you may be too close to the end of your rifle and are getting a reading off of your muzzle blast.
I set my unit up at least 15' from the end of the rifle. 20' is I'm shooting boomers. You can proof your unit using match 22 ammo. The velocities on the box are usually pretty close to actuality.

Chronographs can sometimes be affected by time and weather. I've had misreadings near sundown where I put a paper on the side in order to get correct readings. And one misty day I had everything reading about 200 fps too fast. I still don't know what was causing that.

In general, of course, the 1% accuracy figure is a good rule of thumb. We can't expect reliable, repeatable accuracy inside of 30 fps with portable units on the market.

tough to expect precision from a 60 dollar chronograph. I had two chronys and neither one was reliable or was calibrated right. One went back to the factory to get it calibrated and it came back just as bad as it went in. they charged me to calibrate it but i doubt they even put a screw driver to it.

A "chronograph" giving unexpected Velocity readings and creating confusion.

Someone on this Board has mentioned that in the past.

I think I must have been a bit too close then. I had my unit about 6 feet from the end of the barrel. I'm thinking must be some of the muzzle flash. Back to the drawing board. Thanks for your help and insight.

Your unit may have been a tad close, but your results don't totally surprize me either. Those VLD probably have a much smaller bearing surface, which develops less pressure, and velocity. I think your results may be fairly accurate based on the variables in the components. But make sure your chrony isn't getting rocked with muzzle blast.

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A "chronograph" giving unexpected Velocity readings and creating confusion.

Has anyone ever noticed that it's always the inexpensive chronograph brands that their owners have problems with? I guess the old time adage of, "you get what you paid for" fits chronographs to a tee. Why would anyone expect top-of-the-line performance from bargain-basement equipment? Beats me.

Did anyone on AR advise you RenegadeRN, to buy an Oehler Research chronograph with their patented 3 proof channel skyscreens? Which is actually 2 chronographs in 1, both checking against each other for accuracy.

I suppose some folks think it's easy to clock a tiny projectile going 2200 mph over a 1' long course. Then fold that equipment up and put it in your back pocket for the trip home.

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Originally posted by ted thorn:
I check mine each time I use it with my .22LR just to be sure I am square and parallel to the unite before I waste any center fire ammo. It also lets me verify the speed as being the same as the last session.

This sounds like a good idea. Or you could use a load from this rifle or another rifle that has been clocked with someone's chrony for a check.

Some folks drive an Escalade to and from their job at the 7/11. But is it practical?

I proofed my cheap assed Chrony when I got it against two other chronographs of much higher cost. It was right on. It has given me 20 years of good service by telling me how fast my bullets are going. About the only thing it doesn't do for me is give me the ability to say "Ha Ha, I spent a whole lot more for my stuff than you did."

Thanks everyone. I wanted to ensure I using the chrono correctly. And thanks Dave. Why yes, I considered all options and even the one as you mentioned. I sincerely thank you for your insight. Unfortunately I do not have as DEEP a pocket as one might wish to have. And you are 100% correct. You do get what you pay for.

However, I do not need a Countach to get to work or cruise mainstreet, nor do I need to shoot a Perazzi at clay targets to realize the exhilaration of Sporting Clays. My Jimmy works fine as does my Remmy. However, I am also aware that Murphy or any manner of gremlins do visit from time to time. And since this is my first foray into chronographs and was just guessin' that a .300WinMag was not typically pushing 180 grain bullets to 3700fps I inquired as to what my issue might have been. As you pointed out, I suspected maybe the unit itself could be the problem. I wanted to inquire if this could have been an issue and if I should send it back to the factory for service. But before I did so I wanted to be sure what everyone's opinion was they used as the distance from muzzle to first diffuser.

"This is my chrono, there are many like it, but this one is mine. My chrono is my friend. It is my life. I must master it as I must master my life...." LOL!

Thanks everyone for helping me troubleshoot this.

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Originally posted by onefunzr2:

quote:

A "chronograph" giving unexpected Velocity readings and creating confusion.

Has anyone ever noticed that it's always the inexpensive chronograph brands that their owners have problems with? I guess the old time adage of, "you get what you paid for" fits chronographs to a tee. Why would anyone expect top-of-the-line performance from bargain-basement equipment? Beats me.

Did anyone on AR advise you RenegadeRN, to buy an Oehler Research chronograph with their patented 3 proof channel skyscreens? Which is actually 2 chronographs in 1, both checking against each other for accuracy.

I suppose some folks think it's easy to clock a tiny projectile going 2200 mph over a 1' long course. Then fold that equipment up and put it

in your back pocket for the trip home.

Do you have any data showing that your contentions are worth listening too?

I've had two sub $200 chronos and I have tested them against 2 different Oehler's a 35p and a 43 PBL. My cheap chronographs matched right up with Oehlers.
I often used to create my own "proof channel" by placing my units right in line and shooting through both (2 different makes) at the same time. Both read exactly what you'd expect them to read.
It's not rocket science to measure crystal oscillations and they oscillate at a very precise rate.
Would I love to have a 43 PBL? You bet I would but primarily for the pressure measurements rather than any increased accuracy.

I don't think it has been said but to me it is very important to set up a target behind the Chrony.

This gives you a visual spot that allows you to consistently have accurate bullet placement over the eyes of the machine. This is a absolute MUST….shoot at the same spot.

quote:

Originally posted by ted thorn:

I don't think it has been said but to me, it is very important to set up a target behind the Chrony.

I'd assume lots of people do this. I set a target at 100 yards so I can sight-in and get velocities with the minimum number of rounds expended. Here's how I'd do it: Get a laser sighter that fits in the chamber. Play the laser onto the target at 100 yards. Clip a sheet of paper across the rear uprights on the chrono. Adjust the chrono's position to get the laser hitting in the center of the paper. I'm thinking this procedure will banish those maddening ERR1 and ERR2 messages. It should also put an end to murdered chronos...

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Originally posted by dla:

quote:

Originally posted by onefunzr2:

quote:

A "chronograph" giving unexpected Velocity readings and creating confusion.

Has anyone ever noticed that it's always the inexpensive chronograph brands that their owners have problems with? I guess the old time adage of, "you get what you paid for" fits chronographs to a tee. Why would anyone expect top-of-the-line performance from bargain-basement equipment? Beats me.

Did anyone on AR advise you RenegadeRN, to buy an Oehler Research chronograph with their patented 3 proof channel skyscreens? Which is actually 2 chronographs in 1, both checking against each other for accuracy.

I suppose some folks think it's easy to clock a tiny projectile going 2200 mph over a 1' long course. Then fold that equipment up and put it

in your back pocket for the trip home.

Do you have any data showing that your contentions are worth listening too?

My 'contention,' and you don't have to read between the lines to get it, was not that an Oehler Research chronograph is more accurate in reading a bullet's speed. It was that the only folks who ever post on AR asking for help are those who do not own an Oehler product. My only 'data' to support that 'contention' is this forum's search function of posts from the last 11 years...go ahead and use it yourself. You'll see that the only ones pulling their hair out trying to figure out why their chrono isn't giving an accurate speed readout are non-Oehler users. There's got to be a reason.

And it's not because Oehler has a more accurate crystal clock than other chronographs. But they do have patented skyscreen detectors...that's where it matters most. And they have the proof channel. It's patented too.

Did you ever wonder why every other chrono brand is compared against an Oehler? And why no one in the ammunition industry or government artillery proving grounds use a Chrony brand chronograph...and you know government contracts go out to the low bidder, if they meet the standards.

No one ever bought a Chrony thinking it was the best; it was bought cause it was CHEAP. But, as usually the case when buying on the CHEAP, you end up fiddling, fussing and frustrated when you keep using up your ammo supply and only have ERROR to show for it? Whodothunkit?

IMO, bargain basement chronographs with their crappy reputation have done the most to give the whole chronograph industry a bad name.

Have you ever seen an Oehler brand chronograph with a bullet hole in it?


To quote comedian Gilbert Gottfried: SON-OF-A-BITCH!

Onefun, there are several errors in your obserrvations.

"Has anyone ever noticed that it's always the inexpensive chronograph brands that their owners have problems with? I guess the old time adage of, "you get what you paid for" fits chronographs to a tee. Why would anyone expect top-of-the-line performance from bargain-basement equipment? Beats me."

One, the problems most have come from lack of well written instructions, such as settng the instrument back far enough to avoid muzzle blast more than any real lack of "quality".

Two, few who buy Chrony instruments are rarely deluded by thinking they will have "the best", they don't need the best and know it, what they want is something they can afford without pinching the family budget and that is easy/convenient to set up and use.


".. Oehler Research chronograph ... is actually 2 chronographs in 1, both checking against each other for accuracy."

Incorrect; the Oehler is ONE chronograph. It has one clock, one computer. It's different only that it has two "stop" signals, from the second and third screens, and the count is simply done twice for the two intervals and then compared for gross errors. That way it does give warning if the effects of muzzle blast was present. The first timer reading does not increase accuracy of the end results at all.

And do you seriously think, or want us to think, Oehlers are less prone to getting shot than others?


It seems to me that each of us should choose our chronographs as we do everything else, for its features and value to fit our real needs, not by price alone. And not to have our choices denegrated by those who choose to pay more, perhaps so they might feel superiour to presumed lesser mortals?

I don't use a Chrony. What I use is of no interest to anyone but me, but I sure don't try to cruch down on those who don't use what I - or you - use.

quote:

It's different only that it has two "stop" signals, from the second and third screens, and the count is simply done twice for the two intervals and then compared for gross errors.

I agree and apologize for being inarticulate in my description.

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And do you seriously think, or want us to think, Oehlers are less prone to getting shot than others?

Yes I do. I have never seen the guts shot out of a model, 33, 35 or 43 Oehler like the above two Chronys. Have you? My chrono sits on the benchrest behind the muzzle. How it could get punched by a bullet is beyond me.

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And not to have our choices denegrated by those who choose to pay more, perhaps so they might feel superiour to presumed lesser mortals?

If that's what you thought I was trying to do by pointing out, "you get what you paid for," you're wrong and a straw man argument. I never said those who didn't buy my (Oehler) brand of chronograph were fools, stupid or 'trying to cruch' (sic) down on them. All I said was, what do you expect?

Not finding 'well written instructions' would be my first clue that I was about to spend more time fiddling with my equipment and asking 'how do I get it to work' on internet chatrooms than using a quality product that works the first time, every time.

I don't care if anyone ever again buys another piece of Oehler equipment; I have no stock in Dr. Ken Oehler's company.

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I don't use a Chrony.

I wonder why?

Yes I have seen a set of Oehler skyscreens blown to heck.

Likely cost more to replace them than buying a new Shooting Chrony too.

Chrony's sell at rate of 10000 to 1 over Oehler. So I expect to see a few pictures of shot up Chrony's. And of course, as any thinking person knows, pictures of shot up Chrony's are totally irrelevant since Oehler's aren't bullet proof.

since we're using AR as a resource, anytime someone wants to know a good chronograph to buy, the "pro Chrony" post far exceed any other chronograph. Of course, there is gonna be a certain number of "mine cost more so's it's got to be better" posts but few can even begin to explain WHY their's is better.
As posted, the sales of Chronys far exceeds all of the rest combined so simple logic would tell you that there will be more post, good and bad, about Chronys. Kinda like Remington rifles.

Folks arguing and fighting over chronographs -

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Originally posted by ted thorn in a different thread:
"If you don't have anything nice to say than don't say anything at all"

"If you don't have anything constructive to add, please subtract" ...

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Originally whammed in by the ALWAYS amiable Hot Core:
"Can't we all just get along?!?!?!!?!?" - drug-using, brain-dead Rodney King 1992.

I can be nice and constructive and still disagree.

Because our name has already been mentioned in a few posts, I'll make a few comments and pose a question.

The crystal clock frequency and accuracy, along with the time counting and computation, are almost trivial in handloader chronographs. Over the years we've had dozens of requests from college students ready to design their whiz-bang chronograph. They have mastered all the oscillator, counter, computation, and display elements; would we please tell them how to start and stop their timer?

The skyscreens and the associated "front-end" circuits are the keys to chronograph accuracy and reliability. We've been looking for fifty years, but have found no cheap and easy way to do it right.

Chronographs display a velocity computed from a measured time and an assumed distance. We can measure the time between two signals very precisely, but how do you know exactly how far the bullet traveled between these two time signals?

We can accurately measure the spacing between start and stop screens, but how far did the bullet actually travel between the time marks?

KenOehler

Renegade. In my experience, the velocities you are reporting on your 180gr load do seem a little off. If I thought they could be reliabley repeated, I'd be in the market for a 300 WM!!

In the 25 years I've been chronoghaphing, I've seen more then one result that's made me scratch my head....and I always did exactly what you are doing....asked the question why. Understanding the why's are what will make you a better reloader.

I've managed to wear out my chrony, and I'm ready for another one....so as a chrony user here are my thoughts.

As previously mentioned chronograph distance. If you have one of the "Master" models, always run the unit out to the end of the cord. If you have a standard unit, 10-12 feet is a good distance.

Make sure it's opend PERFECTLY FLAT. A slighly closed chrony can result in a 500 fps difference in the velocity range you are describing.

Cloudy days are best for chronographing. It's not unusualy to get erratic readings on bright crystal clear, blue sky days.

Temperature will affect velocity. My rule of thumb, going from 70 degrees to 100 degrees adds 100 fps. Going fm 70 degrees to 30 degrees subtracts 100 fps.

The Chronograph is a very valuable tool for the reloader, but just like any other insturment, you need to know when something is funny and ask, "Why is that?"

My suggestion would be to make the adjustments described, retest, and let us know how it goes!